std:: isdigit (std::locale)

#include <iostream>
#include <locale>
#include <string>
#include <unordered_set>
struct jdigit_ctype : std::ctype<wchar_t>
{
    std::unordered_set<wchar_t> jdigits{
        L'一', L'二', L'三', L'四', L'五', L'六', L'七', L'八', L'九', L'十'
    };
    bool do_is(mask m, char_type c) const override
    {
        return (m & digit) && jdigits.contains(c)
            ? true // 日语数字将被分类为数字
            : ctype::do_is(m, c); // 其余交由父类处理
    }
};
int main()
{
    std::wstring text = L"123一二三１２３";
    std::locale loc(std::locale(""), new jdigit_ctype);
    std::locale::global(std::locale("en_US.utf8"));
    std::wcout.imbue(std::locale());
    for (const wchar_t c : text)
        if (std::isdigit(c, loc))
            std::wcout << c << " is a digit\n";
        else
            std::wcout << c << " is NOT a digit\n";
}